diff --git a/include/generic_object.hpp b/include/generic_object.hpp
index d3b51a3..0d2e45d 100644
--- a/include/generic_object.hpp
+++ b/include/generic_object.hpp
@@ -59,7 +59,7 @@ namespace character {
 
         [[nodiscard]] virtual std::uint32_t add_damage() const noexcept = 0;
 
-        [[nodiscard]] virtual std::uint32_t add_materiel(const characteristic::characType inType) const noexcept = 0;
+        [[nodiscard]] virtual std::int32_t add_materiel(const characteristic::characType inType) const noexcept = 0;
 
         [[nodiscard]] virtual std::string_view to_string() const noexcept = 0;
 
@@ -86,7 +86,7 @@ namespace character {
 
         [[nodiscard]] std::uint32_t add_damage() const noexcept final;
 
-        [[nodiscard]] std::uint32_t add_materiel(const characteristic::characType inType) const noexcept final;
+        [[nodiscard]] std::int32_t add_materiel(const characteristic::characType inType) const noexcept final;
 
         [[nodiscard]] std::string_view to_string() const noexcept final;
 
@@ -112,7 +112,7 @@ namespace character {
 
         [[nodiscard]] std::uint32_t add_damage() const noexcept final;
 
-        [[nodiscard]] std::uint32_t add_materiel(const characteristic::characType inType) const noexcept final;
+        [[nodiscard]] std::int32_t add_materiel(const characteristic::characType inType) const noexcept final;
 
         [[nodiscard]] std::string_view to_string() const noexcept final;
 
@@ -138,7 +138,7 @@ namespace character {
 
         [[nodiscard]] std::uint32_t add_damage() const noexcept final;
 
-        [[nodiscard]] std::uint32_t add_materiel(const characteristic::characType inType) const noexcept final;
+        [[nodiscard]] std::int32_t add_materiel(const characteristic::characType inType) const noexcept final;
 
         [[nodiscard]] std::string_view to_string() const noexcept final;
 
diff --git a/src/generic_object.cpp b/src/generic_object.cpp
index 00e194d..c83cccb 100644
--- a/src/generic_object.cpp
+++ b/src/generic_object.cpp
@@ -30,7 +30,7 @@ namespace character {
 
     std::uint32_t Weapons::add_damage() const noexcept { return type == weapons::Morgenstern ? 1 : 0; }
 
-    std::uint32_t Weapons::add_materiel(const characteristic::characType inType) const noexcept {
+    std::int32_t Weapons::add_materiel(const characteristic::characType inType) const noexcept {
         switch (type) {
             case weapons::Sword:
                 if (inType == characType::Habilete) {
@@ -93,12 +93,14 @@ namespace character {
 
     std::uint32_t Equipments::add_damage() const noexcept { return 0; }
 
-    std::uint32_t Equipments::add_materiel(const characteristic::characType inType) const noexcept {
+    std::int32_t Equipments::add_materiel(const characteristic::characType inType) const noexcept {
         switch (type) {
             case equipments::Chainmail:
-                return inType == characType::Habilete ||
-                       inType == characType::Adresse ||
-                       inType == characType::Endurance ? 1 : 0;
+                if (inType == characType::Habilete ||
+                    inType == characType::Adresse) {
+                    return -1;
+                }
+                return inType == characType::Endurance ? 1 : 0;
             case equipments::CookingPot:
                 return inType == characType::Endurance ? 2 : 0;
             case equipments::PamphletTourist:
@@ -127,7 +129,7 @@ namespace character {
 
     std::uint32_t Tools::add_damage() const noexcept { return 0; }
 
-    std::uint32_t Tools::add_materiel(const characteristic::characType inType) const noexcept {
+    std::int32_t Tools::add_materiel(const characteristic::characType inType) const noexcept {
         switch (type) {
             case tools::Fourche:
                 switch (inType) {